The invention relates to an internal combustion engine having a noise-suppressing encapsulation and a blower for ventilation of said encapsulation, cooling air ducts being formed within the encapsulation by means of partitions through which the cooling air flows in two parallel partial streams, one of said cooling air ducts comprising all fuel and oil leading engine parts as injection pump, injection pipes and injection nozzles, crankcase, oil pan, gear case and so on, the other cooling air duct being imperviously divided from the first, comprising the parts of the exhaust system arranged within the encapsulation.